I doubt that they would start using the 119 Sat for any more than tHey already do ...
If they were to do that, they would have to go out to each sub that will potentially get anything off the 119 and put up a different LNB again.
They are trying to reduce the truck rolls ...
The way I think it is going to work is this:
1) mirror 95/119 onto reverse band (they are in the process of this now, channels are in "TEST")
2) all new residential installs get SL3RB (already the case, except for few limited cases where people get SL5RB)
3) one of two things happens, not certain which happens first but either:
3a) T16 launches and goes live, enabling 8 new transponders at 103ca, OR
3b) Directv shuts down MPEG2 SD on 101, allowing some HD channels to move there, thus freeing up Ka on 99/103
4) the 95/119 "mirror" moves to Ka
5) 95 & 119 are shut down
The reason why I think 95/119 content won't remain on reverse band in the long term is because of MDUs. In order to have the channels on 95/119 on reverse band, the MDUs not only need to swap in a legacy reverse band LNB they also need to replace the SWM8/SWM16/SWM32 switches with DSWM30s - at least for any tenant who needs to access channels on reverse band.
Now maybe there's a big effort underway where Directv is telling MDUs "you need to have this done by <some date later this year>" but that sounds like a pretty big project so it just seems easier to put those channels on Ka so the MDUs can take their time and won't need to be fully "reverse band ready" until 4K channels start using reverse band. No idea when that will happen, but since there's still no sign of real 4K channels on the horizon and a lot of Ka bandwidth will be freed up by the end of this year, they can probably put it off for a few more years at least if they choose to.